On 09/06/2010 01:15 AM, Amos Jeffries wrote:
Inspired from the SuSE patch submitted by Christian. This is what I
think should be happening with real ptr maths instead of obsolete
integer math with potential rounding and endian errors.


void
memNodeWriteComplete(void* d)
{
    mem_node* n = (mem_node*)(d - _mem_node_data_offset);

GCC: pointer of type void * used in arithmetic


The value of a (pointer + n) expression depends on what pointer is pointing to. If you want byte-size increments, you have to cast to char* or similar.

Using ptrdiff_t instead of int is the right thing to do. I do not thing you need to cast to it in makeMemNodeDataOffset. You may clarify the intent by writing:

// calculate data member offset; p is not dereferenced here
mem_node *p = 0;
return reinterpret_cast<char*>(&p->data) - reinterpret_cast<char*>(p);


HTH,

Alex.

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